Acorn dual drive--hybrid retrofit
Posted: Wed Jan 03, 2018 11:03 pm
Acorn retrofit underway on Romi cnc lathe
the retrofit is a hybrid entity--when Acorn board is off and no computer/software active
the lathe functions perfectly using encoder pulses from manual pulse generator wired directly to step drives
this system requires DRO verification of positioning---this should be installed on all open loop controls
such as Acorn--cnc 12 software provides confirmation of code execution only--there is no feedback loop from
any positioning verification hardware
what you see in pics and video is Anilam dro hardwired into encoders mechanically coupled to rotor shaft of
step motors this is a dead accurate system and allows verification of position commands issued by cnc 12
program
or--if the handwheels on the carriage are used --precise positioning for od turning, boring, etc
if you examine the acrylic sheet on which the Acorn board is mounted you will note two reed relays of 4 contacts
each--the default no power state allows handwheel operation along with full manual control of spindle motor
and as many e-stop mushroom heads as you wish to be plumbed in a normally closed circuit
this is an attractive system to consider for several reasons--many fundamental turning or milling functions are
enabled with no computer or software in the shop --an additional kink is each microstep of axis stepper motor is calibrated to move axis 0.0002 inch
so--you can count clicks and precisely position--as illustrated in video
I have a Hardinge cnc lathe modified to perform taper turning and metric/imperial threading with no computer no software
using binary filters--a more advanced discussion
Centroid is not threatened by this in any way
Acorn facilitates --and of course profiling, threading, contouring is software dependant
a simple toggle switch activating the 24 vdc colis in the relays switches to cnc 12/Acorn and disables handwheels
DRO confirmation remains active--
video clip and pics
https://www.youtube.com/watch?v=bsJ4EVv ... e=youtu.be
the retrofit is a hybrid entity--when Acorn board is off and no computer/software active
the lathe functions perfectly using encoder pulses from manual pulse generator wired directly to step drives
this system requires DRO verification of positioning---this should be installed on all open loop controls
such as Acorn--cnc 12 software provides confirmation of code execution only--there is no feedback loop from
any positioning verification hardware
what you see in pics and video is Anilam dro hardwired into encoders mechanically coupled to rotor shaft of
step motors this is a dead accurate system and allows verification of position commands issued by cnc 12
program
or--if the handwheels on the carriage are used --precise positioning for od turning, boring, etc
if you examine the acrylic sheet on which the Acorn board is mounted you will note two reed relays of 4 contacts
each--the default no power state allows handwheel operation along with full manual control of spindle motor
and as many e-stop mushroom heads as you wish to be plumbed in a normally closed circuit
this is an attractive system to consider for several reasons--many fundamental turning or milling functions are
enabled with no computer or software in the shop --an additional kink is each microstep of axis stepper motor is calibrated to move axis 0.0002 inch
so--you can count clicks and precisely position--as illustrated in video
I have a Hardinge cnc lathe modified to perform taper turning and metric/imperial threading with no computer no software
using binary filters--a more advanced discussion
Centroid is not threatened by this in any way
Acorn facilitates --and of course profiling, threading, contouring is software dependanta simple toggle switch activating the 24 vdc colis in the relays switches to cnc 12/Acorn and disables handwheels
DRO confirmation remains active--
video clip and pics
https://www.youtube.com/watch?v=bsJ4EVv ... e=youtu.be